The raw material for building rammed earth walls can be sourced locally almost anywhere.
This is the local gravel pit, when this picture was taken the house we were building was only about 2 km away. The raw material is loaded into the crusher that crushes the larger rocks and screens the mix to a diameter of 3/4″ or less. The sand and smaller percentage of finely distributed silt and clay are naturally occurring and already mixed in with the stone.